Polymers have been widely used for biomedical purposes such as medical devices, tissue engineering scaffolds, and drug carriers for drug delivery system (DDS). Using polymers for such medical devices should be entirely sensible, as polymers are generally very soft, highly cost-effective, and relatively biocompatible. In order to encourage further development in the biocompatibility of the polymers for the enhanced use of the materials, the functionalization of the polymer surfaces has been deliberately introduced. Plasma modification is one of the most efficient ways for the surface treatment of polymers, since plasma treatment could selectively modify the chemical and the physical properties of the surface of the polymers by not affecting the original bulk characteristics of the polymers. Also, plasma surface modification offers shorter treatment time as compared with other surface modification methods. When plasma was applied to the polymer surface, functional groups, graft polymerization, coatings, and molecular crosslinking formation would be introduced with or without the change in the surface roughness of the polymer. The highly functionalized polymers by the plasma modifications would be effectively used for the materials in tissue engineering or drug delivery systems. In this paper, the fabrication and the characterization of polymers by several types of plasma treatments are reviewed, followed by the introduction of their applications to the materials in drug delivery systems and tissue engineering.

Surface modification of polymers by plasma treatments for the enhancement of biocompatibility and controlled drug release

Photolithographic patterning of organic materials and plasma-based transfer of photoresist patterns into other materials have been remarkably successful in enabling the production of nanometer scale devices in various industries. These processes involve exposure of highly sensitive polymeric nanostructures to energetic particle fluxes that can greatly alter surface and near-surface properties of polymers. The extension of lithographic approaches to nanoscale technology also increasingly involves organic mask patterns produced using soft lithography, block copolymer self-assembly, and extreme ultraviolet lithographic techniques. In each case, an organic film-based image is produced, which is subsequently transferred by plasma etching techniques into underlying films/substrates to produce nanoscale materials templates. The demand for nanometer scale resolution of image transfer protocols requires understanding and control of plasma/organic mask interactions to a degree that has not been achieved. For manufa...

Plasma-polymer interactions: A review of progress in understanding polymer resist mask durability during plasma etching for nanoscale fabrication

https://iopscience.iop.org/article/10.1088/1361-6463/aa748a/pdf

New developments in surface functionalization of polymers using controlled plasma treatments

The uncontrolled development of nanoscale roughness during plasma exposure of polymer surfaces is a major issue in the field of semiconductor processing. In this paper, we investigated the question of a possible relationship between the formation of nanoscale roughening and the simultaneous introduction of a nanometer-thick, densified surface layer that is formed on polymers due to plasma damage. Polystyrene films were exposed to an Ar discharge in an inductively coupled plasma reactor with controllable substrate bias and the properties of the modified surface layer were changed by varying the maximum Ar+ ion energy. The modified layer thickness, chemical, and mechanical properties were obtained using real-time in situ ellipsometry, x-ray photoelectron spectroscopy, and modeled using molecular dynamics simulation. The surface roughness after plasma exposure was measured using atomic force microscopy, yielding the equilibrium dominant wavelength λ and amplitude A of surface roughness. The comparison of mea...

Relationship between nanoscale roughness and ion-damaged layer in argon plasma exposed polystyrene films

https://iopscience.iop.org/article/10.1088/1361-6595/aaa86c/pdf

Foundations of low-temperature plasma enhanced materials synthesis and etching

Results are presented from molecular dynamics (MD) simulations of 100eV Ar+ bombardment of a model polystyrene (PS) surface. The simulations show that the system transitions from an initially high sputter yield (SY) for the virgin polymer to a drastically lower SY as steady state is approached. This is consistent with corresponding ion beam experiments. The MD indicates that this drop in SY is due to the formation of a heavily cross-linked, dehydrogenated damaged layer. The thickness and structure of this layer are also consistent with ellipsometry and x-ray photoelectron spectroscopy measurements of Ar plasma-exposed PS samples.

J. J. Vegh

Papers

Relationship between nanoscale roughness and ion-damaged layer in argon plasma exposed polystyrene films

Near-surface modification of polystyrene by Ar+: Molecular dynamics simulations and experimental validation